Around 2015; world conflicts make people inmigrate to Japan. The japanese worried about the ever growing population; in a family called Gowa, they began creating certain military devices to controll the inmigration.
Yushirou Gowa is the youngest son of the Gowa family; and he can summon the supernatural "Gasaraki" while dancing the Gasara dance to please his family. There is also a girl called Miharu who can also summon the Gasaraki.
What is the Gasaraki? And how come only Yushirou and Miharu can summon it? This and an arupting war can all be answered in this series.